The three landmark traumas that have scarred our history over the past 72 years each scarred us in its own way. The assassination of John F. Kennedy, 50 years ago today, was a political event with historic consequences, but it was also the cause of deep, personal mourning on a national scale.

The other two events had a broader impact. Pearl Harbor brought the United States into World War II. Sept. 11 precipitated two wars and produced a long period of discord and disquiet.

Kennedy’s assassination did not produce a war — though it is still debated whether in elevating Lyndon Johnson to the presidency it eventually yielded the Vietnam War. Rather, his death touched a deep chord of disappointment and loss.

A review of photos from the era captures the feeling. Kennedy is sunny, handsome, young — at the helm of a sailboat or at a lectern in the Rose Garden. He was among the wave of young parents who had passed through the crucible of World War II and were busy producing the baby boom generation. He and Jackie, living at the White House with their two young children, seemed to mirror all the new families finding new homes in the blossoming new communities of America.

Though it has been fashionable in recent years to downplay Kennedy’s liberalism, noting instead his slowness on civil rights and his aggressive posture in the Cold War, Kennedy’s presidency was a liberal moment in our history.

He was slow on civil rights, but that’s because he was confronted with the entrenched racism of the South. (Even Lyndon Johnson had a hard time wresting civil rights gains from Congress.) Even so, when the time came, Kennedy did what he needed to do, calling out the National Guard in defiance of governors in Mississippi and Alabama, meeting with the Rev. Martin Luther King Jr. and other civil rights leaders, introducing a civil rights bill.

Our liberal moment involved a can-do spirit that is sometimes difficult to recall. After the slumberous Eisenhower years, Kennedy initiated the mission to the moon. He pushed for the creation of Medicare. He sought a tax cut that would help working people. He pushed for a nuclear test ban treaty. He established the Peace Corps. Kennedy had persuaded people that government was capable of achieving great things.

Kennedy’s death affected the nation in a personal way because he had touched the people in a personal way. Photos from the aftermath of the assassination remind us of the depth of the tragedy. There was Robert Kennedy, his trusted attorney general and grief-harrowed brother, appearing by Jackie’s side throughout the ceremonies in Washington. There were the two lovely children, whose father had been taken from them. (Yes, John-John did salute.) There was Edward Kennedy, the kid brother, the callow senator, with much growing up to do. The nation partook of their pain; the nation’s loss echoed their loss.

Eisenhower had been the beloved father figure, the great war leader, an emblematic figure of an earlier generation. Kennedy had ushered us into a new era, full of possibility, not free of conflict, but with a trajectory toward progress. That our progress was soon thwarted by war, lies and criminality only left us with a sense of possibilities lost.

Where were you when Kennedy was shot? Of those who remember, many were in school, observing the astonishment of their teachers, witnessing the adult world rocked by the unpredictable contingencies of history and life. In the days that followed, they continued to be rocked by astonishing events that included the on-air murder of the assassin, the grand spectacle of the funeral and the formation of a new administration to take us into an uncertain future.